https://www.luogu.com.cn/problem/AT_ddcc2019_final_a

#include <iostream>
#include <cstdio>
using namespace std;
int n, m, l;
string s;
double r; 
int main(){
	cin>>n>>s;
	for(int i=0; i<n; ++i){
		if(s[i]=='>'){ 
			r+=1.0/(l+2); // 答案更新
			l++; // 记录
		}
		else r+=1, m=max(m, l), l=0;
	}
	printf("%.15lf\n", r-1+1.0/(m+2)); // at 不换行，爆 0 两行泪
	return 0;
}